Polar vortex freezes U.S. Midwest

The polar vortex is bringing deadly cold weather to large areas of the U.S. for the second time since 2014


Polar Vortex: Spinning pool of cold air normally circles stratosphere over North Pole

Sudden warming above North Pole caused by blast of hot air from Morocco in December is causing polar vortex to drift south

Jet stream: Pushed south

Temperatures dropping as low as -30C in Midwest 

Warm air

Chicago


Scientists debating whether polar vortexes are occurring more frequently, and if this is due to
climate change


Air temperature at 2 metres
(Degrees Celsius), Jan 29
-40 -20 0 20 40


Sources: NASA, National Weather Service
Picture: NASA
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